2012 GMC SIERRA 1500 engine

Black plate (35,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-35
Starter Switch Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular brake.
See Parking Brake on
page 9‑54.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral). If the vehicle starts in any other
position, contact your dealer for
service.Automatic Transmission
Shift Lock Control
Function Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Firmly apply the parking brake. See Parking Brake on
page 9‑54.
Be ready to apply the regular
brake immediately if the vehicle
begins to move. 3. With the engine off, turn the
ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check
While parked, and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position.
.The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park).
.The ignition key should come
out only in LOCK/OFF.
Contact your dealer if service is
required.

Black plate (36,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-36 Vehicle Care
Park Brake and P (Park)
Mechanism Check
{WARNING
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
.To check the P (Park)
mechanism's holding ability:
With the engine running, shift
to P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear or cracking.
See Maintenance Schedule on
page 11‑3 for more information on
wiper blade inspection.
Replacement blades come in
different types and are removed in
different ways. To remove the wiper
blade:
1. Pull the windshield wiper arm connector away from the
windshield.
2. Squeeze the grooved areas on
each side of the blade, and turn
the blade assembly away from
the arm connector.

Black plate (40,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-40 Vehicle Care
3. When replacing a bulb on thepassenger side, remove the
Engine Air Cleaner cover. See
Engine Air Cleaner/Filter on
page 10‑17 for more information.
4. Reach in and access the bulb sockets from inside the engine
compartment.
5. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
6. Unplug the electrical connector from the old bulb by releasing
the clips on the bulb socket.
7. Replace it with a new bulb.
8. Plug in the electrical connector.
9. Reinstall the new bulb socket into the headlamp assembly and
turn it clockwise to secure.Pick-Up Box Identification
and Fender Marker
Lamps
The pick-up box identification lamps
are LEDs. For replacement of the
LED lighting assembly contact your
dealer.
To replace a pickup box fender
marker lamp bulb:
1. Press the tab from the back toremove the lamp.
2. Turn the bulb socket counterclockwise to remove
from the lamp assembly.
3. Gently pry the bulb from the socket.
4. Install the new bulb in socket.
5. Reinstall socket into lamp assembly.
6. Reinstall the lamp assembly.
Taillamps (Chassis Cab
Models)
A. Backup Lamp
B. Stoplamp/Taillamp/Turn Signal Lamp
To replace one of these bulbs:
1. Remove the four screws.
2. Lift the lens off the lamp assembly.
3. Turn the old bulb counterclockwise and pull the
it straight out from the socket.

Black plate (44,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-44 Vehicle Care
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have
the headlamp wiring checked right
away if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit
Breakers
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
The wiring circuits in the vehicle
are protected from short circuits
by a combination of fuses, circuit
breakers and fusible thermal links.
This greatly reduces the chance of
fires caused by electrical problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.If you ever have a problem on the
road and don't have a spare fuse,
you can borrow one that has the
same amperage. Just pick some
feature of your vehicle that you can
get along without–
like the radio or
accessory power outlet– and use its
fuse, if it is the correct amperage.
Replace it as soon as you can.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax Diesel supplement
for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.

Black plate (45,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-45
The Engine Compartment Fuse
Block is located in the engine
compartment, on the driver side of
the vehicle.
Lift the cover to access the fuse
block.
Notice:Spilling liquid on any
electrical component on the
vehicle may damage it. Always
keep the covers on any electrical
component.
To remove fuses, hold the end of
the fuse between your thumb and
index finger and pull straight out.
Fuses Usage
1 Right Trailer Stop/
Turn Lamp
2 Electronic Suspension
Control, Automatic Level
Control Exhaust
3 Left Trailer Stop/
Turn Lamp Fuses
Usage
4 Engine Controls
5 Engine Control Module,
Throttle Control
6 Trailer Brake Controller
7 Front Washer
8 Oxygen Sensor

Black plate (46,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-46 Vehicle Care
FusesUsage
9 Antilock Brakes System 2
10 Trailer Back-up Lamps
11 Driver Side Low-Beam
Headlamp
12 Engine Control Module
(Battery)
13 Fuel Injectors, Ignition
Coils (Right Side)
14 Transmission Control
Module (Battery)
15 Vehicle Back-up Lamps
16 Passenger Side
Low-Beam Headlamp
17 Air Conditioning
Compressor
18 Oxygen Sensors
19 Transmission Controls
(Ignition)
20 Fuel Pump
21 Fuel System Control
Module Fuses
Usage
22 Not Used
23 Not Used
24 Fuel Injectors, Ignition
Coils (Left Side)
25 Trailer Park Lamps
26 Driver Side Park Lamps
27 Passenger Side Park
Lamps
28 Fog Lamps
29 Horn
30 Passenger Side
High-Beam Headlamp
31 Daytime Running
Lamps (DRL)
32 Driver Side High-Beam
Headlamp
33 Daytime Running Lamps 2
34 Sunroof
35 Key Ignition System, Theft
Deterrent System Fuses
Usage
36 Windshield Wiper
37 SEO B2 Upfitter Usage
(Battery)
38 Electric Adjustable Pedals
39 Climate Controls (Battery)
40 Airbag System (Ignition)
41 Amplifier
42 Audio System
43 Miscellaneous (Ignition),
Cruise Control
44 Not Used
45 Airbag System (Battery)
46 Instrument Panel Cluster
47 Power Take-Off
48 Auxiliary Climate Control
(Ignition)
49 Center High-Mounted
Stoplamp (CHMSL)
50 Rear Defogger

Black plate (47,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-47
FusesUsage
51 Heated Mirrors
52 SEO B1 Upfitter Usage
(Battery)
53 Accessory Power Outlet
54 SEO Upfitter Usage
55 Climate Controls (Ignition)
56 Engine Control Module,
Secondary Fuel Pump
(Ignition)
J-Case Fuses Usage
57 Cooling Fan 1
58 Not Used
59 Heavy Duty Antilock
Brake System
60 Cooling Fan 2
61 Antilock Brake
System 1 J-Case
Fuses Usage
62 Starter
63 Stud 2 (Trailer Brakes)
64 Left Bussed Electrical
Center 1
65 Not Used
66 Not Used
67 Transfer Case
68 Stud 1 (Trailer
Connector
Battery Power)
(Optional - 40A Fuse
Required)
69 Mid-Bussed Electrical
Center 1
70 Climate Control Blower
71 Not Used
72 Left Bussed Electrical
Center 2 Relays
Usage
FAN HI Cooling Fan High
Speed
FAN LO Cooling Fan Low
Speed
FAN CNTRL Cooling Fan
Control
HDLP
LO/HID Low-Beam
Headlamp
FOG LAMP Front Fog Lamps
A/C
CMPRSR Air Conditioning
Compressor
STRTR Starter
PWR/TRN Powertrain
FUEL PMP Fuel Pump
PRK LAMP Parking Lamps
REAR
DEFOG Rear Defogger
RUN/CRNK Switched Power

Black plate (54,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-54 Vehicle Care
(F) Tire Ply Material:The type
of cord and number of plies in
the sidewall and under the tread.
(G) Single Tire Maximum
Load
:Maximum load that can
be carried and the maximum
pressure needed to support that
load when used as a single. For
information on recommended
tire pressure see Tire Pressure
on page 10‑58 andVehicle Load
Limits on page 9‑16.
Tire Designations
Tire Size
The examples show a typical
passenger vehicle and light
truck tire size.
Passenger (P‐Metric) Tire
(A) Passenger (P‐Metric) Tire:
The United States version of a
metric tire sizing system. The
letter P as the first character in
the tire size means a passenger
vehicle tire engineered to
standards set by the U.S. Tire
and Rim Association.
(B) Tire Width
:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 75, as shown in
item C of the tire illustration, it would mean that the tire's
sidewall is 75 percent as high
as it is wide.
(D) Construction Code
:A
letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of
the wheel in inches.
(F) Service Description
:These
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
is certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.